Medical balloon with coextruded radiopaque portion

ABSTRACT

A balloon catheter includes an elongated, tubular shaft having a proximal end and a distal end, and a balloon positioned along the distal end of the shaft. A portion of a wall of the balloon partially comprises a coextruded radiopaque material. Related aspects and methods are also disclosed.

This application is a continuation of U.S. application Ser. No.14/383,767, which is a National Stage of PCT/US2013/029977, which claimspriority to U.S. Provisional 61/608,913 and Netherlands Application No.2008450 filed Mar. 9, 2012, the disclosures of which are incorporatedherein by reference.

TECHNICAL FIELD

This disclosure relates generally to balloons for performing medicalprocedures, such as angioplasty and, more particularly, to a medicalballoon having a coextruded radiopaque portion.

BACKGROUND OF THE INVENTION

Balloons are routinely used to resolve or address flow restrictions orperhaps even complete blockages in tubular areas of the body, such asarteries or veins. In many clinical situations, the restrictions arecaused by hard solids, such as calcified plaque, and require the use ofhigh pressures to compact such blockages. Commercially availableballoons employ complex technology to achieve high pressure requirementswithout sacrificing the profile of the balloon. Besides high pressurerequirements, the balloons should also be resistant to puncture, easy totrack and push, and present a low profile, especially when used forangioplasty.

In clinical practice, angioplasty balloons are expanded from a deflated,folded state to an expanded state within a vessel to treat a targetarea, such as a portion of the circumferential inner wall I of a bloodvessel V, as shown in FIGS. 1 and 2. The inflation of a balloon 12 withwall 28 is traditionally completed using an X-ray contrast agent CMalong dimension DX to provide better visibility under X-ray or otherform of radiography R during the interventional procedure, asillustrated in FIGS. 3 and 3 a (which shows the intensity measured by afluoroscope detector plate, FDP). Typically, a 70/30 percent mixture ofcontrast agent and saline is used to inflate the balloon during anangioplasty procedure.

In general, a desirable goal is to reduce inflation and deflation timesrequired for balloons without sacrificing the profile of the balloons,especially for large volume balloons (which can require up to twominutes of inflation/deflation times with the contrast agent). Becauseof its relatively high viscosity, it would also be desirable toeliminate, or at least reduce the amount of, the contrast agent used ininflation/deflation of the balloons. The use of contrast agent prolongsthe inflation/deflation times and also poses the risk of iodine exposureto patients sensitive to iodine. In this regard, a non-radiopaquesubstance could be used in lieu of the contrast agent, such as forexample saline or carbon dioxide, but such substances are invisibleduring X-ray imaging, and thus do not enhance visibility.

Furthermore, the physician performing the angioplasty procedure shouldbe able to locate the position of the uninflated balloon with accuracy,so that the balloon will be properly positioned once inflated. This isconventionally accomplished by attaching marker bands on the cathetershaft in the region corresponding to the balloon working surface. This“working surface” is the surface along the portion of the balloon thatis used to achieve the desired treatment effect, such as contacting thecalcified plaque (which surface in the case of a balloon having conicalor tapering sections at the proximal and distal ends is typicallyco-extensive with a generally cylindrical barrel section).

Misalignment of the marker bands during placement along the shaftsometimes results in their failure to correspond precisely to the extentof the working surface, as is shown in FIG. 4 (note misalignment amountX between each interior marker band M carried by shaft S and workingsurface W of balloon 12, which also typically includes a radiopaque tipP at the distal end). Even upon exercising great care to position themarkers properly on the underlying shaft in alignment with anticipatedboundaries of the working surface when the balloon is inflated, thereremains a tendency for mismatch due to several possible factors. Onesuch factor may be the tolerance stack-ups arising as a consequence ofthe affixation of the balloon to the distal end of the catheter shaft.The balloon also has a tendency to grow in the longitudinal directionwhen inflated, especially with large and particularly long balloons.Another factor is the tendency of the portion of the catheter shaftwithin the balloon to bend or flex during inflation. This may lead tomisalignment between radiopaque markers fixed to the shaft and theworking surface.

Whatever the cause, the resulting misalignment may prevent the clinicianfrom accurately identifying the location of the working surface of theballoon during an interventional procedure. This may lead to ageographic misplacement, or “miss,” of the intended contact between thetarget area T and the working surface W of the balloon 12 (see FIG. 2).It is especially desirable to avoid such an outcome when the balloon isdesigned to deliver a payload (such as a drug, stent, or both) or aworking element to a specified location within the vasculature, since amiss may prolong the procedure (such as, for example, by requiringredeployment of the balloon 12 or the use of another balloon catheter inthe case of a drug coated balloon).

Upon deflation, the balloon may also be subject to a phenomenon known as“pancaking” In this condition, the balloon 12 folds down upon itself toa flattened state, as shown in FIG. 5. This situation may cause theballoon to be viewed through fluoroscopy as perhaps still being in theinflated condition, since the full width of the balloon may still beperceived. This can give the clinician the false perception that theballoon remains inflated, when in fact it is not.

Accordingly, the need is identified for a balloon for which the workingsurface may be identified during an interventional procedure withenhanced precision. The solution would take into account the possiblemismatch between fixed locations on the catheter shaft and the balloonto define the working surface, and would operate independent of theposition of the portion of the catheter shaft within the balloon. Theimproved identification may also allow for the better detection of thefalse perception of deflation caused by pancaking. Overall, proceduralefficiency would be enhanced without remarkably increasing cost orcomplexity, and in a manner that can be applied to many existingcatheter technologies without extensive modification.

SUMMARY OF THE INVENTION

An object of the disclosure is to provide a balloon having a coextrudedradiopaque portion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-9 are illustrative of the background of the invention;

FIG. 10 illustrates a first embodiment according to the disclosure;

FIG. 11 illustrates a second embodiment according to the disclosure;

FIGS. 12 and 12 a are cross-sectional views of certain embodiments;

FIG. 13 illustrates a third embodiment according to the disclosure;

FIG. 14 illustrates a fourth embodiment according to the disclosure;

FIG. 15 illustrates the embodiment of FIG. 14 in a folded condition;

FIG. 16 illustrates a fifth embodiment according to the disclosure;

FIGS. 17 and 18 illustrate a sixth embodiment according to thedisclosure;

FIG. 19 illustrates a manufacturing technique;

FIGS. 20-23 illustrate various embodiments according to the disclosure;and

FIGS. 24-28 illustrate other embodiments according to the disclosure.

MODES FOR CARRYING OUT THE INVENTION

The description provided below and in regard to the figures applies toall embodiments unless noted otherwise, and features common to eachembodiment are similarly shown and numbered.

Provided is a catheter 10 having a distal portion 11 with a balloon 12mounted on a catheter tube 14. Referring to FIGS. 6, 7, and 8, theballoon 12 has an intermediate section 16, or “barrel,” and end sections18, 20. In one embodiment, the end sections 18, 20 reduce in diameter tojoin the intermediate section 16 to the catheter tube 14 (and thussections 18, 20 are generally termed cones or cone sections). Theballoon 12 is sealed at balloon ends (proximal end 15 a and distal end15 b) on the cone sections 18, 20 to allow the inflation of the balloon12 via one or more inflation lumens 17 extending within catheter tube 14and communicating with the interior of the balloon 12.

The catheter tube 14 also includes an elongated, tubular shaft 24forming a guidewire lumen 23 that directs the guidewire 26 through thecatheter 10, and along the distal end of which the balloon 12 may belocated. As illustrated in FIG. 8, this guidewire 26 may extend throughthe proximal end of the catheter 10 and a first port 25 of a connector27 into the lumen 23 to achieve an “over the wire” (OTW) arrangement,but could also be provided in a “rapid exchange” (RX) configuration, inwhich the guidewire 26 exits a lateral opening 14 a closer to the distalend (see FIG. 9) or else is fed through the tip distally of the balloon12 (not shown). A second port 29 may also be associated with catheter10, such as by way of connector 27, for introducing a fluid (e.g.,saline, a contrast agent, or both) into the interior compartment of theballoon 12 via the inflation lumen 17.

Balloon 12 may include a single or multi-layered balloon wall 28 formingthe interior for receiving the inflation fluid. The balloon 12 may be anon-compliant balloon having a balloon wall 28 that maintains its sizeand shape in one or more directions when the balloon is inflated.Examples of non-compliant balloons may be found in U.S. Pat. No.6,746,425 and Publication Nos. US 2006/0085022, US 2006/0085023 and US2006/0085024, the disclosures of which are hereby incorporated herein byreference. The balloon 12 in such case also has a pre-determined surfacearea that remains constant during and after inflation, also has apre-determined length and pre-determined diameter that each, ortogether, remain constant during and after inflation. However, theballoon 12 could be semi-compliant or compliant instead, depending onthe particular use.

In order to provide for enhanced locatability during an interventionalprocedure, the balloon 12 may have a radiopaque quality. In oneembodiment, this radiopaque quality is provided in a manner that allowsfor a clinician to differentiate, with relative ease and high precision,one portion of the balloon 12 from another (such as, but not limited to,the barrel section 16 including the working surface W from the conesections 18, 20). This helps the clinician ensure the accuratepositioning of the balloon 12 and, in particular, a portion of or theentire working surface W, at a specified treatment location, which maybe especially desirable in the delivery of drugs via the balloon workingsurface W, as outlined in more detail in the following description.

In one embodiment, and with initial reference to FIGS. 10 and 11, theradiopaque quality is achieved by providing strategically positionedidentifiers, such as one or more at least partially radiopaque markings30. The markings 30 are provided at one or more locations along theballoon 12 to create a defined portion as the working surface W. Forexample, a marking 30 may be provided extending along the balloon 12 ina longitudinal direction. For instance, the marking 30 may be providedin the form of at least one longitudinal strip 36, as shown in FIG. 10.More than one strip 36 may be provided, each being spaced in thecircumferential direction, either irregularly or equidistantly (e.g.,two strips offset at 180 degrees, three strips offset 120 degrees fromeach other, four strips offset 90 degrees from each other). For example,FIG. 11 may be considered a top plan view of the balloon 12 withtransparency (or as it may appear under fluoroscopy) to show thepresence of at least three strips (but four would appear substantiallysimilar, if spaced apart equidistantly, with the top and bottom stripsalign at the twelve and six o'clock positions, respectively). Asdescribed in more detail below, the strips 36 may also be formed so asto comprise all or only a portion of the cross-sectional thickness ofthe balloon wall 28, as shown in FIG. 12 (partial) and FIG. 12a (full),and may be along an outer or inner surface of the balloon wall 28.

As may be understood by comparing FIGS. 10 and 11, the one or morestrips 36 may extend the entire length L of the balloon 12, or mayextend only over a portion of it, such as the working surface W of thebarrel section 16. With reference to FIGS. 13 and 14, one or more of themarkings 30, such as strips 36, may also extend along all or a portionof one or both of the cone sections 18, 20. Indeed, the use of aplurality of strips, 36 such as two, three, or four or more, along oneor both of cone sections 18, 20 only may allow the clinician to morereadily detect the existence of pancaking, since the strips would appearto be farther apart when the balloon 12 is inflated, and closer when theballoon 12 is deflated (12′) and not flattened (compare FIGS. 14 and15).

In one or more of these embodiments, the balloon 12 including theradiopaque markings 30 may be formed using co-extrusion techniques.Turning to the schematic depiction in FIG. 16, this may be achieved byusing an extrusion apparatus 100 including a first die 101 with one ormore ports corresponding to the desired number of radiopaque strips 36in the balloon 12, and a second, adjacent die 102 with ports forproviding the carrier material, together arranged to form a tubularcoextruded structure. For example, in the case where six ports areprovided in the first die 101, the co-extrusion process would form sixradiopaque portions 104 in a tubular parison 106, as shown in FIGS. 17and 18. The material between the radiopaque portions 104 is thenon-radiopaque carrier material 108, which in the illustrated embodimentcompletely encloses and encases the embedded radiopaque portions 104.

In any case, the parison 106 with the one or more radiopaque portionsmay be cut to any desired length. The cut parison 106 may then be placedinto a mold cavity 150 (such as by separating two mating mold portions)and expanded, such as by blow molding under heat and pressure (FIG. 19).The result is the finished, at least partially radiopaque balloon 12having markings 30, with a shape (e.g., with cone sections 18, 20, andbarrel section 16) conforming to the interior contour of the mold cavity(which in the case of only one co-extruded radiopaque portion in theparison, may have the appearance when molded of the balloon 12 in FIG.10).

In another embodiment, a tube 200 may be formed via coextrusion havingone or more radiopaque portions 202, as shown in FIG. 20 and previouslydescribed. This tube 200 may then be bonded to non-radiopaque tubes 204,such as by welding, to create a tubular parison 206 (FIG. 21) that is atleast partially radiopaque. This parison 206 may then be expanded toform the corresponding balloon 12, such as by blow molding. In the caseof a parison 206 having three or four radiopaque portions 204, theresulting expanded balloon 12 (taking into account elongation) may havethe appearance of the FIG. 11 embodiment, with the working surface Wdelineated by the resulting strips 36.

An alternative is to provide two tubes 302 a, 302 b (which may beportions of tube 300), and connect these to the opposed ends of a tube300 having no added radiopacifier, to create a parison 306 (FIGS. 22 and23). Upon being expanded, this parison 306 could form an embodiment ofthe balloon 12 similar to the one shown in FIG. 13. As should beappreciated, the FIG. 13 embodiment could also be formed in a similarmanner by bonding the tube 300 to a single, co-extruded tube 302 a or302 b having a radiopacifier (which, if tube 302 a or 302 b had three ormore radiopaque portions, could be used to create the FIG. 14embodiment).

The balloon 12 with the radiopaque quality may also be formed bycoextruding a radiopaque material with a non-radiopaque materialtogether in an overlapping manner to create a multi-layered parison. Forexample, as shown in FIG. 24, a parison 400 may be created bycoextruding one or more layers of a radiopaque material 402 with amaterial 404 without any added radiopacifier. This could be done to forma balloon 12 that is entirely radiopaque along the length L (such as byblow molding the parison 400), or one that is partially radiopaque. Forexample, as shown in FIG. 25, the multi-layered parison 400 could beattached to tubes 406, 408 having no added radiopacifier. The bondedtubes 400, 406, 408 may then be expanded in a mold to create a balloon12 having a radiopaque quality extending along the working surface Wonly (FIG. 26). Likewise, a tube without any added radiopacifier couldbe bonded to one or two performs formed as in FIG. 24 and blown tocreate a balloon 12 with the radiopaque markings along one or both ofthe cone sections 18, 20 (FIG. 26a ).

In any case, the forming may be done by coextruding theradiopaque-enhanced and non-radiopaque-enhanced materials together in acontinuous fashion, as described previously, or an intermittent fashion(such as to provide the strip 36 along the portions of the tubecontinuously formed to create the cone sections or barrel section of thefinished balloon). As noted above with respect to FIGS. 12 and 12 a,strategically selecting the thickness of the coextruded materials mayallow for a more precise control of the radiopacity of the strips 36(e.g., a thicker strip would include more radiopacifier and be morereadily discernable). Likewise, such control may be achieved byadjusting the relative amount of radiopacifier in the correspondingmaterial for providing the strips 36 during the co-extrusion process.

Balloons 12 that carry one or more surface elements, such as a payload(drug, stent, or both) or a working implement (cutter, focused forcewire, or the like) into the vasculature may also benefit from theforegoing description of marking techniques. For example, as shown inFIG. 10, a balloon 12 including a defined working surface W, such as byproviding radiopaque markings 30 at the transitions between the barrelsection 16 and cone sections 18, 20, may include a portion coated withsuch a drug D, such as one designed for achieving a desired therapeuticeffect when applied to the interior of the vessel. The radiopaquemarking 30 may also correspond to the location of the drug D on theballoon 12, such as along the entire working surface W or only a portionof it. The drug D may be applied to the inflated balloon as part of themanufacturing process, and prior to folding for insertion in thevasculature. The clinician may thus with the benefit of a fluoroscopedetermine the precise positioning of the working surface W prior toinflating the balloon 12 in the vasculature to deliver the drug D to thedesired location and provide the desired treatment regimen.

In a further embodiment, a balloon may be formed of a multi-layeredstructure, such as by co-extrusion of a parison 500, so as to provide anouter layer 502 that is radiopaque (FIG. 27, cross sectional view),which may extend the full length of the parison (and thus form a balloon12 that is radiopaque in its entirety) or along only a portion of theballoon. The balloon 12 when inflated may then be etched (by solvent,acid, laser, or other material removal process) in a regular orirregular pattern 504 to remove a portion of the outer layer 502, suchas along all or a portion of the working surface W. As shown in FIG. 28,drug D may then be applied to the etched pattern 504, either along theetched portion or the un-etched portion, such as by spraying, painting,coating, or the like. In either case, the extent of the portion of theballoon 12 including the drug D is readily determinable underfluoroscopy during the procedure, as the remaining radiopaque portionspermit easy identification for delivery.

Examples of radiopaque materials include, but are not limited to,thermoplastic films including finely divided tungsten, tantalum,bismuth, bismuth trioxide, bismuth oxychloride, bismuth subcarbonate,other bismuth compounds, barium sulfate, tin, silver, silver compounds,rare earth oxides, and many other substances commonly used for X-rayabsorption. The polymer used for making these films may be any polymericmaterial which can be loaded with radiopacifier and formed into asufficiently thin film. Examples of polymers include thermoplastic andthellnoset polymers. Some examples of thermoplastic polymers include,but are not limited to, polyurethanes, polyamides (nylon 11, nylon 12),polyether-polyamide copolymers such as PEBAX, polyethylene terephthalateor other polyesters, polyvinyl acetate, polyvinyl chloride, and manyother thermoplastic materials useful for making films. Some examples ofthermoset polymers include, but are not limited to, crosslinkedpolyurethanes, polyureas, epoxies, acrylics, silicones, and many otherthermoset materials that can be formed into thin structures, includingfilms.

Any adjacent material, such as the carrier or a layer, may be formed ofa compatible material to that used to form the radiopaque portion. Thisavoids the need for additional processing or the inclusion of acompatibilizer, tie layer or the like. In one embodiment, the radiopaquematerial comprises expanded polytetrafluoroethylene (ePTFE), which inthe form of a strip 36 corresponding to the working surface W maystretch along with the inflation of the balloon 12 and retract ondeflation.

The subject matter of each of the paragraphs below citing a balloon or acatheter can be part of a balloon or a catheter respectively that iscited in any of the other paragraphs:

-   1.1 A balloon catheter, comprising: an elongated, tubular shaft    extending in a longitudinal direction, said shaft having a proximal    end and a distal end; and an inflatable balloon supported along the    distal end of the shaft, the balloon when inflated including first    and second spaced conical end sections and a working surface between    the conical sections, the balloon further including at least one    radiopaque marking identifying the transition from the conical end    section to the working surface.-   1.2 The catheter of paragraph 1.1, wherein the at least one    radiopaque marking comprises a first radiopaque marking at a first    transition between the first conical end section and the working    surface, and further including a second radiopaque marking at a    second transition between the second conical end section and the    working surface.-   1.3 The catheter of any of the foregoing paragraphs, wherein the at    least one marking comprises a strip.-   1.4 The catheter of any of the foregoing paragraphs, further    including a plurality of radiopaque markings in the form of strips.-   1.5 The catheter of paragraph 1.4, wherein the strips extend at    least partially in a longitudinal direction between the first and    second conical end sections.-   1.6 The catheter of paragraphs 1.4 or 1.5, wherein the strips    comprise annular bands.-   1.7 The catheter of any of the foregoing paragraphs, wherein at    least two spaced radiopaque markings are provided on each conical    end section, including one adjacent a distal portion and a proximal    portion of each conical end section.-   1.8 The catheter of any of the foregoing paragraphs, wherein the    balloon includes a barrel section between the first and second    conical end sections, and further including a plurality of    radiopaque markings on the barrel section.-   1.9 The catheter of any of the foregoing paragraphs, wherein the    marking comprises a first pattern on the conical end sections and    further including a second, different pattern on the working    surface.-   1.10 The catheter of any of the foregoing paragraphs, wherein the at    least one marking is selected from the group consisting of a    pattern, a strip, a brand, a logo, a letter, a number, a word, or    combinations thereof.-   1.11 The catheter of any of the foregoing paragraphs, wherein the    identifier comprises a scale.-   1.12 The catheter of any of the foregoing paragraphs, wherein the    balloon includes a drug.-   1.13 The catheter of paragraph 1.12, wherein the drug corresponds to    the location of the radiopaque marking.-   1.14 The catheter of paragraph 1.12, wherein the drug corresponds to    other than the location of the radiopaque marking.-   1.15 The catheter of paragraph 1.12, wherein the radiopaque marking    comprises the drug formulated to include a radiopacifier.-   1.16 A balloon having a drug carried on a working surface of the    balloon wall and a radiopaque identifier identifying the location of    the drug on the balloon.-   1.17 The balloon of paragraph 1.16, wherein the radiopaque    identifier comprises a radiopaque material mixed with a formulation    comprising the drug.-   1.18 The balloon of paragraph 1.16, wherein the working surface is    along a barrel section of the balloon, and the radiopaque identifier    is on one or both cone sections of the balloon.-   2.1 A balloon catheter, comprising: an elongated, tubular shaft    extending in a longitudinal direction, said shaft having a proximal    end and a distal end; and an inflatable balloon supported along the    distal end of the shaft, the balloon when inflated including a    generally cylindrical barrel section forming a working surface, and    generally conical end sections that do not form a part of the    working surface, the balloon further including at least one    radiopaque identifier for indicating the relative position of the    working surface, said identifier being provided on at least one of    the conical end sections of the balloon so as to define the extent    of the working surface.-   2.2 The catheter of paragraph 2.1, wherein the identifier comprises    a marking.-   2.3 The catheter of paragraph 2.1 or 2.2, wherein a first marking is    provided at a first transition between the first conical section end    section and the working surface and a second marking is provided at    a second transition between the second end section and the working    surface.-   2.4 The catheter of paragraph 2.2 or 2.3, wherein the marking    comprises a strip.-   2.5 The catheter of any of the foregoing paragraphs, wherein the    identifier comprises a longitudinal strip extending between an end    of the balloon and the barrel section.-   2.6 The catheter of any of the foregoing paragraphs, further    including a plurality of identifiers.-   2.7 The catheter of paragraph 2.6, wherein each of the plurality of    identifiers comprises a longitudinally extending strip.-   2.8 The catheter of paragraph 2.6 or 2.7, wherein the identifiers    comprise annular bands.-   2.9 The catheter of paragraph 2.6 or paragraph 2.8 as dependent on    paragraph 2.6, wherein the identifiers comprise longitudinally    extending strips.-   2.10 The catheter of any of the foregoing paragraphs 2.1 to 2.9,    wherein at least two spaced radiopaque identifiers are provided on    each end section.-   2.11 The catheter of any of the foregoing paragraphs 2.1 to 2.10,    further including at least one radiopaque identifier on the barrel    section.-   2.12 The catheter of any of the foregoing paragraphs 2.1 to 2.11,    wherein the identifier is a first identifier comprising a first    pattern, and further including a second identifier comprising a    second, different pattern.-   2.13 The catheter of any of the foregoing paragraphs 2.1 to 2.12,    wherein the identifier includes at least one letter or number.-   2.14 The catheter of any of the foregoing paragraphs 2.1 to 2.13,    wherein the identifier comprises a logo.-   2.15 The catheter of any of the foregoing paragraphs 2.1 to 2.14,    wherein the identifier comprises a scale.-   2.16 The catheter of any of the foregoing paragraphs 2.1 to 2.15,    further including a drug on the balloon.-   3.1 An inflatable balloon for use in connection with a catheter,    comprising: an inflatable body including a working surface extending    in a longitudinal direction between a first end and a second end,    the body having at least one radiopaque identifier provided along    the body for identifying at least a first end of the working    surface, the radiopaque identifier having a first radiographic    quality for identifying the location of the first end of the working    surface and a second radiographic quality at a location other than    at the first end of the working surface.-   3.2 The balloon of paragraph 3.1, wherein the second radiographic    quality is provided for identifying the second end of the working    surface.-   3.3 The catheter of paragraph 3.2, wherein the first radiographic    quality and the second radiographic quality are substantially the    same.-   3.4 The balloon of paragraph 3.1, wherein the radiopaque identifier    comprises a marking.-   3.5 The balloon of paragraph 3.1, wherein the radiopaque identifier    follows a generally helical path from the first end to the second    end of the working surface.-   3.6 The balloon of paragraph 3.1, wherein the identifier comprises a    plurality of helical identifiers extending along the working    surface.-   3.7 The balloon of paragraph 3.1, wherein the identifier comprises a    radiopaque filament.-   3.8 The balloon of paragraph 3.7, wherein the filament is wound    helically along at least a portion of the working surface of the    balloon.-   3.9 The balloon of any of the foregoing paragraphs 3.1 to 3.8,    further including a drug on the balloon.-   3.16 A balloon for use in connection with a catheter, comprising: a    body having an outer surface and at least one winding extending    along the outer surface of the balloon, said balloon having a    radiopaque quality.-   3.17 The balloon of paragraph 3.16, wherein the winding comprises a    radiopaque filament.-   3.18 The balloon of any of the foregoing paragraphs, wherein the    radiopaque identifier comprises a helical pattern or a diamond    pattern.-   3.19 A catheter including the balloon of any of the foregoing    paragraphs.-   3.20 An inflatable balloon for use in connection with a catheter    comprising a radiopaque identifier comprising a helical pattern or a    diamond pattern.-   4.1 A balloon catheter for use in connection with a guidewire,    comprising: an elongated, tubular shaft extending in a longitudinal    direction, said shaft having a proximal end and a distal end; an    inflatable balloon supported along the distal end of the shaft, the    balloon when inflated including first and second spaced ends and a    working surface between the ends; and at least one wire including at    least a radiopaque portion for identifying the location of working    surface of the balloon.-   4.2 The catheter of paragraph 4.1, wherein said wire comprises a    material having a shape memory for adjusting between a first state    and a second state.-   4.3 The catheter of paragraph 4.1 or 4.2, wherein the at least one    wire extends generally in the longitudinal direction.-   4.4 The catheter of any of the foregoing paragraphs 4.1 to 4.3,    wherein the radiopaque portion is elongated.-   4.5 The catheter of any of the foregoing paragraphs 4.1 to 4.4,    wherein the wire at least partially comprises a polymer.-   4.6 The catheter of any of the foregoing paragraphs 4.1 to 4.5,    wherein the at least one wire is at least partially elastic.-   4.7 The catheter of any of the foregoing paragraphs 4.1 to 4.6,    comprising: a plurality of wires extending generally in the    longitudinal direction, at least one of the wires including at least    a radiopaque portion for identifying the location of working surface    of the balloon.-   4.8 The catheter of any of the foregoing paragraphs 4.1 to 4.7,    wherein at least one wire extends along an outer surface of the    balloon.-   4.9 The catheter of any of the foregoing paragraphs 4.1 to 4.8,    wherein at least one wire extends along an inner surface of the    balloon.-   4.10 The catheter of any of the foregoing paragraphs 4.1 to 4.9,    wherein at least one wire extends from the first end to the second    end of the balloon.-   4.11 The catheter of any of the foregoing paragraphs 4.1 to 4.10,    wherein the radiopaque portion of at least one wire extends along a    portion of the balloon corresponding to the working surface.-   4.12 The catheter of any of the foregoing paragraphs 4.1 to 4.11,    wherein the radiopaque portion of at least one wire extends along    other than along the portion of the balloon corresponding to the    working surface.-   4.13 The catheter of paragraph 4.7 or any of paragraphs 4.8 to 4.12    as dependent on paragraph 4.7, wherein the wires are spaced    substantially equidistantly around a circumference of the balloon.-   4.14 The catheter of any of the foregoing paragraphs 4.1 to 4.13,    wherein the wire includes a compliant or semi-compliant portion.-   4.15 The catheter of any of the foregoing paragraphs 4.1 to 4.14,    wherein at least one end of the at least partially radiopaque wire    is attached to a bond connecting the balloon to the shaft.-   4.16 The catheter of any of the foregoing paragraphs 4.1 to 4.15,    further including a drug provided on the balloon.-   4.17 The catheter of any of the foregoing paragraphs 4.1 to 4.16,    wherein at least one wire at least partially comprises a material    having a shape memory for adjusting between a first state and a    second state.-   4.18 The catheter of paragraph 4.2 or 4.17, wherein the shape memory    material comprises NITINOL.-   5.1 A balloon catheter adapted for use with a guidewire, comprising:    an elongated, tubular shaft extending in a longitudinal direction,    said shaft having a proximal end and a distal end; an inflatable    balloon supported along the distal end of the shaft, the balloon    when inflated including first and second spaced ends and a working    surface between the ends; and an insert located within the interior    compartment of the balloon, the insert including at least a    radiopaque portion separate from the shaft.-   5.2 The catheter of paragraph 5.1, wherein the insert is adapted for    moving relative to the shaft.-   5.3 The catheter of paragraph 5.1 or 5.2, wherein the insert extends    from a first end of the balloon to one end of the working surface.-   5.4 The catheter of any of the foregoing paragraphs 5.1 to 5.3,    wherein the insert comprises a tube made at least partially of a    radiopaque material.-   5.5 The catheter of any of the foregoing paragraphs 5.1 to 5.4,    wherein the insert comprises at least one finger.-   5.6 The catheter of paragraph 5.5, wherein the finger includes a    radiopaque end portion.-   5.7 The catheter of any of the foregoing paragraphs 5.1 to 5.6,    wherein the insert comprises a plurality of fingers adapted for    moving from a retracted condition to an expanded condition when the    balloon is inflated.-   5.8 The catheter of any of the foregoing paragraphs 5.1 to 5.7,    further including a retractable sheath at least partially covering    the insert.-   5.9 The catheter of any of the foregoing paragraphs 5.1 to 5.8,    wherein the insert comprises a wire.-   5.10 The catheter of paragraph 5.9, wherein the wire includes a    radiopaque portion corresponding to the working surface.-   5.11 The catheter of paragraph 5.10, wherein the wire extends from    the first end to the second end of the balloon, and the radiopaque    portion comprises an intermediate portion of the wire.-   5.12 The catheter of paragraph 5.10 or 5.11, wherein the wire    extends from the first end to the second end of the balloon, and the    radiopaque portion comprises an end portion of the wire.-   5.13 The catheter of any of the foregoing paragraphs 5.1 to 5.12,    wherein at least one end of the insert is connected at a location    where the balloon connects to the tubular shaft.-   5.14 The catheter of any of the foregoing paragraphs 5.1 to 5.13,    wherein the insert comprises an annular band.-   5.15 The catheter of any of the foregoing paragraphs 5.1 to 5.14,    wherein the insert includes perforations.-   5.16 The catheter of any of the foregoing paragraphs 5.1 to 5.15,    wherein the insert comprises a material having a shape memory.-   5.17 The catheter of any of the foregoing paragraphs 5.1 to 5.16,    further including a drug on the balloon.-   6.1 A parison for being blow molded into a medical balloon for a    catheter, comprising: a first tubular layer having a functional    modification; and a second tubular layer adapted for bonding with    the first tubular layer to form the blow molded balloon.-   6.2 The parison of paragraph 6.1, wherein the first layer is    external to the second layer.-   6.3 The parison of paragraph 6.1, wherein the first layer is    internal to the second layer.-   6.4 The parison of any of the foregoing paragraphs, wherein the    functional modification comprises a radiopaque strip.-   6.5 The parison of paragraph 6.4, wherein the strip comprises a    circumferential band.-   6.6 The parison of paragraph 6.4 or 6.5, wherein the strip extends    between a first end and a second end of the first layer.-   6.7 The parison of any of the foregoing paragraphs, wherein the    first tubular layer is spaced from the second tubular layer.-   6.8 The parison of any of the foregoing paragraphs, wherein the    functional modification is selected from the group consisting of an    added radiopacifier, a surface pattern, an etching, one or more    perforations, and combinations of the foregoing.-   6.9 A medical balloon formed by the parison of any of the foregoing    paragraphs, comprising: a tubular, inflatable body comprising a    wall, the body including first and second generally conical ends and    a generally cylindrical barrel section between the generally conical    ends and providing a working surface.-   6.10 The balloon of paragraph 6.9, wherein the first layer extends    from the first end to the second end of the balloon.-   6.11 The balloon of paragraph 6.9, wherein the first layer extends    along only the working surface.-   6.12 The balloon of any of paragraphs 6.9 to 6.11, wherein the first    layer extends along an entire circumference of a portion of the    wall.-   6.13 The balloon of any of paragraphs 6.9 to 6.12, wherein the first    layer extends along the full circumference of the wall.-   6.14 The balloon of any of paragraphs 6.9 to 6.13, wherein the wall    includes first and second spaced shoulders, and wherein the first    layer is positioned between the shoulders.-   6.15 The balloon of any of paragraphs 6.9 to 6.14, wherein the first    and second layers both extend from a first end to a second end of    the balloon.-   6.16 The balloon of any of paragraphs 6.9 to 6.15, further    comprising an at least partially radiopaque tube positioned over the    barrel section and extending substantially along the working    surface.-   6.17 The balloon of paragraph 6.16, further including first and    second shoulders adjacent the proximal and distal ends of the    radiopaque tube.-   6.18 The balloon of paragraph 6.16 or 6.17, wherein the entire tube    is radiopaque.-   7.1 A balloon catheter, comprising: an elongated, tubular shaft    having a proximal end and a distal end; and a balloon positioned    along the distal end of the shaft, a portion of a wall of the    balloon partially comprising a coextruded radiopaque material.-   7.2 The catheter of paragraph 7.1, wherein the radiopaque portion    comprises at least one strip extending along a working surface of    the balloon.-   7.3 The catheter of paragraph 7.1 or 7.2, wherein the radiopaque    portion comprises at least one strip extending along a full length    surface of the balloon.-   7.4 The catheter of any of paragraphs 7.1 to 7.3, wherein the    radiopaque portion comprises at least one strip extending along a    first cone section of the balloon.-   7.5 The catheter of paragraph 7.4, wherein the radiopaque portion    comprises at least one strip extending along a second cone section    of the balloon.-   7.6 The catheter of any of paragraphs 7.1 to 7.5, wherein the    balloon includes a plurality of radiopaque portions.-   7.7 The catheter of paragraph 7.6, wherein each of the plurality of    radiopaque portions comprises a longitudinal strip.-   7.8 The catheter of paragraph 7.7, wherein the strips extend at    least along a working surface of the balloon.-   7.9 The catheter of any of paragraphs 7.6 to 7.8, wherein the    plurality of radiopaque portions are spaced apart in a    circumferential direction.-   7.10 The catheter of any of the foregoing paragraphs 7.1 to 7.9,    wherein the balloon includes a barrel section and conical sections    at each end of the barrel section, and wherein the radiopaque    portion is provided on the barrel section.-   7.11 The catheter of any of the foregoing paragraphs 7.1 to 7.10,    wherein the balloon includes a barrel section and conical sections    at each end of the barrel section, and wherein the radiopaque    portion is provided on one or both of the cone sections.-   7.12 The catheter of any of the foregoing paragraphs 7.1 to 7.11,    wherein the radiopaque portion comprises a layer of the balloon    wall.-   7.13 The catheter of paragraph 7.12, wherein the layer comprises an    inner layer.-   7.14 The catheter of paragraph 7.12 or 7.13, wherein the layer    comprises an outer layer.-   7.15 The catheter of paragraph 7.14, wherein the outer layer is    etched.-   7.16 The catheter of any of paragraphs 7.12 to 7.15, wherein the    balloon includes a barrel section and conical sections at each end    of the barrel section, and the layer extends along the entire barrel    section.-   7.17 The catheter of any of paragraphs 7.12 to 7.16, wherein the    balloon includes a barrel section and conical sections at each end    of the barrel section, and the layer extends along the entirety of    one or both of the conical sections.-   7.18 The catheter of any of the foregoing paragraphs 7.1 to 7.17,    wherein all portions of the wall comprise coextruded radiopaque    material.-   7.19 The catheter of any of the foregoing paragraphs 7.1 to 7.18,    further including a drug on the balloon,-   7.20 The catheter of any of the foregoing paragraphs 7.1 to 7.19,    wherein the radiopaque material comprises ePTFE.-   8.1 A balloon catheter, comprising: a shaft extending in a    longitudinal direction, said shaft having a proximal end and a    distal end, and supporting at least one radiopaque identifier; an    inflatable balloon supported along the distal end of the shaft, the    balloon when inflated including a working surface; and an actuator    for aligning at least one end of the working surface with the at    least one radiopaque identifier.-   8.2 The catheter of paragraph 8.1, wherein the actuator includes a    first position corresponding to a deflated state of the balloon and    a second position corresponding to the inflated state of the    balloon.-   8.3 The catheter of paragraph 8.1 or 8.2, wherein the actuator    comprises a spring.-   8.4 The catheter of any of the foregoing paragraphs 8.1 to 8.3,    wherein the spring comprises a leaf spring.-   8.5 The catheter of any of the foregoing paragraphs 8.1 to 8.4,    wherein the actuator comprises a plurality of springs spaced    circumferentially about the catheter.-   8.6 The catheter of any of the foregoing paragraphs 8.1 to 8.5,    wherein a first portion of the actuator is fixed to the balloon and    a second portion of the actuator is adapted for movement relative to    the shaft.-   8.7 The catheter of paragraph 8.6, wherein the first portion of the    actuator is captured between two layers on the wall of the balloon.-   8.8 The catheter of paragraph 8.6 or 8.7, wherein the shaft includes    a channel for at least partially receiving the second portion of the    actuator.-   8.9 The catheter of any of the foregoing paragraphs 8.1 to 8.8,    further including a stop for stopping the movement of the actuator.-   8.10 The catheter of any of the foregoing paragraphs 8.1 to 8.9,    wherein the radiopaque identifier comprises a marker attached to the    shaft.-   8.11 The catheter of any of the foregoing paragraphs 8.1 to 8.10,    wherein the radiopaque identifier comprises an insert positioned    within the interior compartment of the balloon.-   8.12 The catheter of any of the foregoing paragraphs 8.1 to 8.11,    wherein the actuator is a first actuator for aligning a distal end    of the working surface with the radiopaque identifier, and further    including a second actuator for aligning a proximal end of the    working surface with the radiopaque identifier.-   8.13 The catheter of paragraph 8.12, wherein each of the first and    second actuators comprise a plurality of springs.-   8.14 The catheter of any of the foregoing paragraphs, wherein the    radiopaque identifier comprises a first marking and a second    marking, and wherein the actuator is a first actuator for aligning a    distal end of the working surface with the first marking, and    further including a second actuator for aligning a proximal end of    the working surface with the second marking.-   8.15 The balloon catheter of any of the foregoing paragraphs 8.1 to    8.14, comprising: a shaft extending in a longitudinal direction,    said shaft having a proximal end and a distal end, and supporting    first and second radiopaque identifiers; a first actuator for    aligning a first end of the working surface with the first    radiopaque marking; and a second actuator for aligning a second end    of the working surface with the second radiopaque identifier.-   8.16 The balloon catheter of any of the foregoing paragraphs 8.1 to    8.15, comprising: a shaft for carrying the balloon, the shaft    including at least one channel formed in an outer portion of a wall    of the shaft; and an actuator having a first end connected to the    balloon and a second end at least partially positioned in the    channel.-   8.17 The balloon catheter of any of the foregoing paragraphs 8.1 to    8.16, comprising: a shaft for carrying the balloon, the shaft    including a plurality of channels formed in an outer portion of the    wall of the shaft.-   8.18 The catheter of paragraph 8.17, further including an actuator    having a first end connected to the balloon and a second end    positioned in at least one of the channels.-   8.19 The catheter of any of the foregoing paragraphs 8.1 to 8.8,    comprising: a spring connected to a wall of the balloon.-   8.20 The catheter of paragraph 8.19, wherein the spring is at least    partially radiopaque.-   8.21 The catheter of paragraph 8.19 or 8.20, wherein the spring is    connected to a conical section of the wall of the balloon.-   8.22 The balloon catheter of any of the foregoing paragraphs 8.1 to    8.21, wherein the balloon includes a drug.-   9.1 A balloon catheter for use with a guidewire, comprising: an    elongated, tubular shaft extending in a longitudinal direction, said    shaft having a proximal end and a distal end; an inflatable balloon    connected to the distal end of the shaft, the balloon including a    working surface; a radiopaque identifier for identifying the working    surface; and a receiver adjacent the proximal end of the shaft and    adapted for allowing the shaft to move relative to the receiver in    at least the longitudinal direction.-   9.2 The catheter of paragraph 9.1, wherein the shaft carries a stop,    and the receiver further includes a recess for receiving the stop,    said recess having a dimension in the longitudinal direction that is    greater than a corresponding dimension of the stop.-   9.3 The catheter of paragraph 9.2, further including a tube for    supplying an inflation fluid to inflate the balloon, said tube being    connected to the receiver and generally coaxial with the shaft, and    wherein the stop forms a seal with the recess to prevent the    inflation fluid from passing around the shaft.-   9.4 The catheter of paragraph 9.3, wherein the seal comprises an    O-ring arranged coaxially with the shaft.-   9.5 The catheter of paragraph 9.1, wherein the radiopaque identifier    is separate from the shaft.-   9.6 The catheter of paragraph 9.5, wherein the radiopaque identifier    comprises an insert positioned within the interior compartment of    the balloon.-   9.7 The catheter of paragraph 9.6, wherein the insert comprises a    tubular sleeve arranged coaxially with the shaft.-   9.8 The catheter of paragraph 9.6, wherein the insert comprises a    first insert at a proximal end of the balloon and a second insert at    a distal end of the balloon.-   9.9 The catheter of paragraph 9.1, further including a guidewire for    positioning in the shaft.-   9.10 A hub for a balloon catheter having an elongated, tubular shaft    extending in a longitudinal direction, said shaft having a proximal    end and a distal end, and an inflatable balloon connected to the    distal end of the shaft for being inflated by an inflation fluid,    comprising: a body including a receiver for receiving a proximal    portion of the shaft and adapted for allowing the shaft to move    relative to the receiver in at least the longitudinal direction; and    a stop for restraining the movement of the shaft relative to the    body in the longitudinal direction.-   9.11 The hub of paragraph 9.10, wherein the body includes a    guidewire port arranged in communication with the receiver, and    further including an inflation port for introducing the inflation    fluid for inflating the balloon.-   9.12 The hub of paragraph 9.10, wherein the receiver further    includes a recess for receiving the stop, said recess having a    dimension in the longitudinal direction that is greater than a    corresponding dimension of the stop.-   9.13 The hub of paragraph 9.12, wherein the stop forms a seal with    the recess to prevent the inflation fluid from passing.-   9.14 The hub of paragraph 9.10, wherein the stop comprises an    O-ring.-   9.15 A catheter including a guidewire shaft having a distal end    connected to a balloon and at a proximal end mounted for sliding    movement.-   9.16 The catheter of any of the foregoing paragraphs, further    including a drug on the balloon.-   9.17 A catheter comprising a hub for receiving a proximal end of a    guidewire shaft, the shaft being adapted to slidably move in a    restrained manner relative to the hub.-   10.1 A balloon catheter, comprising: an elongated tubular shaft    having a proximal end and a distal end spaced apart in a    longitudinal direction, the shaft along a distal portion including    at least one radiopaque identifier, said distal portion being formed    of a material resistant to elongation in the longitudinal direction;    and an inflatable, non-compliant balloon extending over the distal    portion of the shaft.-   10.2 The catheter according to paragraph 10.1, wherein the balloon    includes a generally cylindrical barrel section positioned between    generally conical sections, said barrel section including a working    surface having at least one edge aligned with the radiopaque    identifier.-   10.3 The catheter according to paragraph 10.2, wherein the    radiopaque identifier comprises a first marker positioned at the at    least one edge of the working surface, and further including a    second marker positioned at the opposite edge of the working surface    in the longitudinal direction.-   10.4 The catheter according to paragraph 10.2, wherein each marker    comprises a radiopaque band swaged to the distal portion of the    shaft.-   10.5 The catheter according to paragraph 10.1, wherein the distal    portion of the shaft comprises a tube adapted for guiding a    guidewire from a proximal end of the balloon to a distal end of the    balloon.-   10.6 The catheter according to paragraph 10.1, wherein at least the    distal portion of the shaft comprises steel.-   10.7 The catheter according to paragraph 10.1, wherein the shaft    comprises steel.-   10.8 The catheter according to paragraphs 10.6 or 10.7, wherein the    steel shaft comprises a stainless steel.-   10.9 The catheter according to paragraphs 10.7 or 10.8, wherein the    steel shaft includes a spiral cut along a portion other than the    distal portion covered by the balloon.-   10.10 The catheter according to paragraphs 10.7 or 10.8, wherein the    steel shaft comprises a polymer layer.-   10.11 The catheter according to paragraph 10.10, wherein the polymer    layer comprises an outer layer of the shaft.-   10.12 The catheter according to paragraph 10.1, wherein the distal    portion of the shaft comprises a polymer shaft including a braid or    mesh.-   10.13 The catheter according to paragraph 10.1, wherein the balloon    includes a generally cylindrical barrel section positioned between    generally conical sections, the distal portion of the shaft    extending from a first end of a first conical section to a second    end of a second conical section.-   10.14 The catheter according to paragraph 10.1, wherein the    non-compliant balloon comprises one or more inelastic fibers.-   10.15 The catheter according to paragraph 10.1, wherein the    non-compliant balloon comprises polyethylene terephthalate.-   10.16 The catheter of any of the foregoing paragraphs 10.1 to 10.15,    further including a drug on the balloon.-   11.1 A balloon catheter, comprising: a shaft extending in a    longitudinal direction and adapted for expanding from a compressed    condition to an expanded condition in the longitudinal direction,    the shaft supporting at least one radiopaque identifier; and an    inflatable balloon positioned along the shaft, the balloon when    inflated including a working surface for aligning with the    radiopaque identifier in at least the expanded condition of the    shaft.-   11.2 The catheter of paragraph 11.1, wherein the expandable shaft    comprises a first portion connected in tandem to an expandable    element.-   11.3 The catheter of paragraphs 11.1 or 11.2, wherein the expandable    element comprises a spring.-   11.4 The catheter of paragraph 11.3, wherein the spring comprises a    coil spring.-   11.5 The catheter of paragraphs 11.3 or 11.4, wherein the spring    comprises a tension coil spring.-   11.6 The catheter of paragraph 11.2, wherein the expandable element    comprises a bellows.-   11.7 The catheter of paragraph 11.2, wherein the expandable element    comprises a fiber matrix.-   11.8 The catheter of paragraph 11.7, further including a spring    associated with the fiber matrix.-   11.9 The catheter of any of paragraphs 11.2-11.8, wherein the    expandable element is inside an interior compartment of the balloon.-   11.10 The catheter of any of paragraphs 11.2-11.8, wherein the    expandable element is outside an interior compartment of the    balloon.-   11.11 The catheter of any of paragraphs 11.2-11.10, wherein the    expandable element connects to one end of the balloon.-   11.12 The catheter of any of paragraphs 11.2-11.10, wherein the    expandable element connects the first portion of the shaft to a    second portion of the shaft.-   11.13 The catheter of any of the foregoing paragraphs 11.1 to 11.12,    wherein the shaft comprises an inflation lumen for delivering an    inflation fluid to the balloon.-   11.14 The catheter of any of the foregoing paragraphs 11.1 to 11.13,    wherein the expandable shaft in at least a partially expanded    condition a port for delivering the inflation fluid to the balloon,    said port being closed when the shaft is in a non-expanded    condition.-   11.15 The catheter of any of the foregoing paragraphs 11.1 to 11.14,    wherein the expandable shaft comprises a first expandable element    connecting a first portion of the shaft to a second portion of the    shaft, and further including a second expandable element connecting    the second portion of the shaft to a third portion of the shaft.-   11.16 The catheter of paragraph 11.15, wherein the first and second    expandable elements comprise first and second coil springs.-   11.17 The catheter of paragraph 11.16, wherein the first and second    coil springs have different spring constants.-   11.18 The catheter of any of the foregoing paragraphs 11.1 to 11.17,    wherein the radiopaque identifier comprises a pair of spaced    radiopaque markers, one positioned in alignment with a first end of    the working surface and another positioned at a second end of the    working surface.-   11.19 The catheter of any of paragraphs 11.15-11.18, wherein the    first and second expandable elements comprise a radiopaque material.-   11.20 The catheter of any of the foregoing paragraphs 11.1 to 11.19,    wherein the radiopaque identifier comprises a spring.-   11.21 The catheter of paragraph 11.2, wherein the expandable element    comprises a spring having a variable spring constant.-   11.22 The catheter of any of the foregoing paragraphs 11.1 to 11.21,    wherein the shaft comprises a guidewire lumen.-   11.23 The catheter of any of the foregoing paragraphs 11.1 to 11.22,    further including a passage adjacent the tip for receiving a    guidewire external to the balloon.-   11.24 The catheter of paragraph 11.2, wherein the first portion is    adjacent a distal end of the shaft.-   11.25 A balloon catheter, comprising: a shaft; a balloon; and an    expandable element adapted for expanding in the longitudinal    direction connecting the shaft to the balloon.-   11.26 The catheter of paragraph 11.25, wherein the expandable    element is selected from the group consisting of a spring, a    bellows, a fiber matrix, or combinations of the foregoing.-   11.27 The catheter of paragraph 11.25 or 26, wherein the expandable    element comprises an encapsulated spring.-   11.28 A balloon catheter comprising a balloon and an inflation lumen    including an expandable element adapted for expanding in the    longitudinal direction for providing a fluid to the balloon.-   11.29 The catheter of any of paragraphs 11.25-11.28, wherein the    expandable element comprises a radiopaque material.-   11.30 The catheter of any of the foregoing paragraphs 11.1 to 11.29,    further including a drug on the balloon.-   12.1 A balloon catheter, comprising: an elongated, tubular shaft    extending in a longitudinal direction, said shaft having a proximal    end and a distal end; and a balloon having an inflation compartment    formed a balloon wall including a working surface, and further    including at least one chamber adjacent to the working surface    adapted for receiving an identifier for identifying the location of    the working surface.-   12.2 The balloon catheter of paragraph 12.1, wherein the shaft    includes a first lumen for supplying a fluid to the chamber.-   12.3 The balloon catheter of paragraph 12.2, wherein the shaft    includes a port between the first lumen and the chamber.-   12.4 The balloon catheter of paragraph 12.2, wherein the shaft    includes a second lumen for supplying a fluid to an interior    compartment of the balloon.-   12.5 The balloon catheter of paragraph 12.4, wherein the shaft    includes a port between the second lumen and the interior    compartment.-   12.6 The balloon catheter of any of the foregoing paragraphs 12.1 to    12.5, wherein the identifier comprises a contrast agent.-   12.7 The balloon catheter of any of the foregoing paragraphs 12.1 to    12.6, wherein the contrast agent comprises a material selected from    the group consisting of a radiopacifier, polyvinyl acetate,    cellulose, a fluid, a liquid, a solid, a powder, or combinations of    the foregoing.-   12.8 The balloon catheter of any of the foregoing paragraphs 12.1 to    12.7, wherein the chamber comprises a first chamber at a proximal    end of the balloon, and further including a second chamber at a    distal end of the balloon.-   12.9 The balloon catheter of paragraph 12.8, wherein the second    chamber is adapted for receiving the identifier from a lumen in the    shaft in fluid communication with the first chamber via a port.-   12.10 The balloon catheter of any of the foregoing paragraphs 12.1    to 12.9, wherein the chamber is generally annular.-   12.11 The balloon catheter of any of the foregoing paragraphs 12.1    to 12.10, wherein the chamber is positioned between a transition    from a barrel section to a conical section of the balloon and an end    of the balloon.-   12.12 The balloon catheter of any of the foregoing paragraphs 12.1    to 12.11, wherein the chamber is provided by a film attached to the    balloon wall.-   12.13 The balloon catheter of any of the foregoing paragraphs 12.1    to 12.12, wherein the chamber is embedded in the balloon wall.-   12.14 The balloon catheter of any of the foregoing paragraphs 12.1    to 12.13, wherein the chamber is provided by a film extending    between the balloon wall and an outer surface of the shaft.

While the disclosure presents certain embodiments to illustrate theinventive concepts, numerous modifications, alterations, and changes tothe described embodiments are possible without departing from the sphereand scope of the present invention, as defined in the appended claims.For example, any ranges and numerical values provided in the variousembodiments are subject to variation due to tolerances, due tovariations in environmental factors and material quality, and due tomodifications of the structure and shape of the balloon, and thus can beconsidered to be approximate and the term “approximately” means that therelevant value can, at minimum, vary because of such factors.Accordingly, it is intended that the present invention not be limited tothe described embodiments, but that it has the full scope defined by thelanguage of the following claims, and equivalents thereof.

1. A method of forming a parison for forming a balloon for a ballooncatheter, comprising: forming a tube as the parison by coextruding aradiopaque-enhanced material and a non-radiopaque-enhanced material inan intermittent fashion.
 2. The method of claim 1, further including thestep of creating a balloon from the tube, the balloon having generallyconical sections and a generally cylindrical section between thegenerally conical sections.
 3. The method of claim 1, wherein theforming step comprises providing a radiopaque strip along portions ofthe tube.
 4. The method of claim 2, further including the step ofcreating a balloon from the tube, the balloon having generally conicalsections and a generally cylindrical section between the generallyconical sections.
 5. The method of claim 1, wherein the coextrudingcomprises coextruding the radiopaque material with the non-radiopaquematerial in an overlapping manner to provide the tube with multiplelayers.
 6. The method of claim 1, wherein the coextruding comprisesusing a first die with one or more ports for the radiopaque-enhancedmaterial corresponding to a desired number of radiopaque portions of thetube, and a second, adjacent die with ports for providing thenon-radiopaque material of the tube.
 7. A method of forming a parisonfor forming a balloon for a balloon catheter, comprising: forming a tubeas the parison by coextruding a radiopaque-enhanced material and anon-radiopaque-enhanced material together at different time intervals.8. The method of claim 7, further including the step of creating aballoon with the tube, the balloon having generally conical sections anda generally cylindrical section between the generally conical sections.9. The method of claim 7, wherein the forming step comprises providing aradiopaque strip along portions of the tube.
 10. The method of claim 9,further including the step of creating a balloon from the tube, theballoon having generally conical sections and a generally cylindricalsection between the generally conical sections.
 11. The method of claim7, wherein the coextruding step comprises coextruding the radiopaquematerial with the non-radiopaque material in an overlapping manner toprovide the partially radiopaque tube with multiple layers.
 12. Themethod of claim 7, wherein the coextruding step comprises using a firstdie with one or more ports for the radiopaque-enhanced materialcorresponding to a desired number of radiopaque portions of the tube,and a second, adjacent die with ports for providing the non-radiopaquematerial of the tube.
 13. A method of forming a parison for forming aballoon for a balloon catheter, comprising: forming a tube as theparison by coextruding a first material having a radiopacifier with asecond material; and adjusting an amount of radiopacity provided by thefirst material during the coextruding.
 14. The method of claim 13,further including the step of creating a balloon with the tube, theballoon having generally conical sections and a generally cylindricalsection between the conical sections.
 15. The method of claim 13,wherein the coextruding step comprises coextruding the first materialand the second material in an overlapping manner to provide the tubewith multiple layers.
 16. The method of claim 13, wherein the formingstep comprises providing the first material so as to form strips onlyalong a portion of the tube.
 17. The method of claim 13, wherein theadjusting step is performed by controlling the thickness of the firstmaterial.
 18. The method of claim 13, wherein the adjusting step isperformed by controlling an amount of radiopacifier in the firstmaterial.
 19. The method of claim 13, wherein the coextruding stepcomprises using a first die with one or more ports for the firstmaterial corresponding to a desired number of radiopaque portions of thetube, and a second, adjacent die with ports for providing the secondmaterial of the tube.
 20. A balloon formed by the parison using themethod of claim 1.